1. Upper airway obstruction: if the patient required an intervention such as:    o Oral airway    o Jaw thrust   o Nasal airway 2. Mild-moderate hypoxaemia (SpO2 of 93–90%) 3. Severe hypoxaemia (SpO2 < 90%) 4. Signs of respiratory distress or impending ventilation failure:   o Accessory muscle use   o Tracheal tug   o Respiratory rate > 20 breaths per minute 5. Patient could not breathe deeply whilst asked for by the PACU nursing staff 6. Patient complaining of upper airway muscle weakness or symptoms of respiratory:   o Difficulty swallowing: ask the patient to swallow a sip of water   o Difficulty speaking   o Difficulty breathing 7. Patient requiring re-intubation in the PACU 8. Clinical evidence or suspicion of pulmonary aspiration after tracheal extubation (gastric contents observed in the oropharynx and hypoxaemia) |